By Jill Szoo Wilson
Have you ever wondered why the New Testament writers so often assume their readers already know what they’re talking about?
One Story. One Covenant. One Messiah is an ongoing series exploring how the Torah, the Prophets, and the Writings shape every page of the New Testament through the lens of Second Temple Judaism and first-century Jewish thought. Rather than treating the New Testament as the beginning of a new theological system, these essays trace the continuity of God’s covenant purposes from Sinai to the Messiah. Readers new to the series may wish to begin with The Son of Man in the Tanakh: Why Jesus Called Himself the Son of Man and The New Testament Was Written by Second Temple Jews, and One Root. Many Branches. Paul’s Answer in Romans 11, which introduces the central themes developed throughout the series.
The expression Yom YHWH, the Hebrew phrase translated “the Day of the Lord,” appears throughout the prophetic books of the Hebrew Bible and stands at the center of the preaching of John the Baptist, Jesus, the apostles, and the book of Revelation. Yet many Christians associate the phrase almost exclusively with the end of the world or the return of Christ. The story begins much earlier.
For the prophets, the Day of the Lord is not simply a future catastrophe or a final judgment. It is the moment when the God of Israel openly reveals himself in history to judge evil, rescue his people, establish justice, and make his kingship known over all creation. It is one of Scripture’s great unifying themes, weaving together Israel’s covenant story, the hope of the prophets, the expectations of Second Temple Judaism, and the proclamation of the New Testament.
To understand the Day of the Lord, however, we must begin long before the prophets first used the phrase. The language itself appears in the prophetic books, but the pattern that gives it meaning reaches back to Israel’s covenant at Mount Sinai. There, the Lord descended upon the mountain in cloud, fire, thunder, earthquake, and the sound of a trumpet as he established his covenant with the people he had redeemed from Egypt. For Israel, Sinai became the defining revelation of what it looked like when the living God came among his people. Centuries later, when the prophets proclaimed the Day of the Lord, they reached instinctively for the imagery of Sinai because it provided the pattern through which Israel understood God’s future coming.
As Israel’s history unfolded, the prophets looked back to Sinai while also looking beyond it. The God who had once descended upon one mountain to establish his covenant would one day reveal himself again, this time before all nations. His coming would confront human rebellion, judge evil, rescue his people, and establish his reign over the whole earth.
With each generation, the prophets expanded that vision. What began at Sinai as Israel’s experience of God’s covenant Lord coming among his people became the hope that he would one day come again to fulfill his covenant promises, judge evil, and establish his righteous kingdom. By the close of the prophetic era, the Day of the Lord had become one of Israel’s defining hopes.
That hope did not disappear when prophecy ceased. During the Second Temple period, faithful Jews continued reading the prophets, discussing their promises, and waiting for God to fulfill them. By the time the New Testament begins, generations of Israelites had been living in expectation of the Day the prophets had proclaimed. This first essay traces how that expectation developed from Sinai through the prophets. The next essay will explore how that prophetic hope shaped the world into which John the Baptist, Jesus, and the apostles began proclaiming the kingdom of God.
From Sinai to the Prophets
Although the expression Yom YHWH, “the Day of the Lord,” first appears in the prophetic books, the ideas that give the phrase its meaning begin much earlier. To understand why the prophets expected the Lord to come again, we must first understand what happened when he came the first time. That story begins at Mount Sinai.
Only a few weeks after Israel’s deliverance from Egypt, the Lord brought the newly redeemed nation to Mount Sinai to establish his covenant with them (Exod. 19). In the ancient world, a covenant was more than a promise. It established a binding relationship between a king and his people, defining both the king’s obligations and the people’s responsibilities. At Sinai, Israel did not simply receive a collection of religious laws. They entered into a covenant with the God who had rescued them from slavery. Before the Law was given, the Lord announced that he himself would descend upon the mountain in the sight of all the people. Israel was instructed to wash its garments, consecrate itself, and remain outside the boundaries surrounding the mountain because the nation was preparing to meet its holy King.
Exodus slows its narrative when that moment arrives. “On the morning of the third day there was thunder and lightning, with a thick cloud over the mountain, and a very loud trumpet blast. Everyone in the camp trembled” (Exod. 19:16). Smoke covered the mountain because “the Lord descended on it in fire” (19:18). The mountain shook violently, and the trumpet grew louder and louder until the Lord spoke from within the cloud. Moses does not describe these details simply to create drama. Each detail reveals something about the God who has come to meet his people.
Fire throughout Scripture regularly accompanies God’s holy presence. It both illuminates and consumes, revealing a God whose holiness cannot be approached casually. The thick cloud both reveals and conceals him. Israel knows the Lord has descended, yet his full glory remains hidden from human sight. The trumpet announces the arrival of the divine King, much as a royal procession in the ancient world was announced before the ruler appeared. Even the mountain trembles. Creation itself responds because its Creator has drawn near.
These details became enormously important because they shaped Israel’s understanding of what it meant for the Lord to come among his people. Every later generation learned this story. Parents told it to their children. Priests read it publicly. Prophets assumed their audiences knew it by heart. Whenever an Israelite heard of a cloud, fire, trumpet blast, earthquake, darkness, or the trembling of the earth, Sinai immediately came to mind. These were no longer merely descriptions of one historical event. They had become Israel’s language for describing the coming of the Lord.
This explains why the prophets repeatedly return to Sinai when they speak about the future. They do not invent an entirely new picture of God’s coming. They describe the future using the imagery Israel already knows. The God who once descended upon one mountain will one day reveal himself again before all nations. His future coming will be greater in scope, but it will reveal the same holy God acting with the same covenant faithfulness.
Moses himself points Israel in this direction before his death. In his final blessing, recorded in Deuteronomy 33, he recalls the Lord’s appearance at Sinai in language that already reaches beyond the wilderness generation: “The Lord came from Sinai and dawned over them from Seir; he shone forth from Mount Paran. He came with myriads of holy ones, with flaming fire at his right hand” (Deut. 33:2). Moses is remembering the covenant at Sinai, yet he describes the Lord as a victorious king advancing across the landscape surrounded by the armies of heaven. The historical event has become a pattern. The God who came once is also the God who will come again.
When the prophets begin speaking about the Day of the Lord, Israel already possesses the theological vocabulary necessary to understand them. They know what it looks like when the Lord appears. They know that his coming reveals holiness, demands covenant faithfulness, and causes creation itself to respond. The prophets are not introducing a new vision of God’s coming. They are calling Israel to remember the God who had already come at Sinai. Before they announce the Day of the Lord, Scripture has already taught Israel what it means for the Lord to come.
Amos: When the Day of the Lord Becomes a Warning
By the eighth century B.C.E., nearly seven hundred years had passed since Israel stood at Mount Sinai. The nation was now divided into two kingdoms. Amos ministered in the northern kingdom of Israel during the reign of Jeroboam II, a period of remarkable prosperity. Israel’s borders had expanded, trade flourished, and the economy was strong. The sanctuaries at Bethel and Gilgal remained busy with worshipers bringing sacrifices to the Lord. By every outward measure, Israel appeared to enjoy God’s blessing.
Under these circumstances, it is easy to understand why many Israelites longed for the Day of the Lord. If the Lord had once descended upon Sinai to establish his covenant, surely he would come again to defend his covenant people. They expected a day when God would defeat Israel’s enemies, vindicate his chosen nation, and establish his rule over the surrounding kingdoms. The Day of the Lord was the fulfillment of Israel’s hope.
Amos overturns that expectation with a single announcement.
“Woe to you who long for the day of the Lord!” he declares. “Why do you long for the day of the Lord? That day will be darkness, not light” (Amos 5:18).
The force of Amos’s words is easy to miss because many modern readers encounter the phrase “Day of the Lord” for the first time in his book. Israel did not. They already understood what it meant for the Lord to come among his people. Amos does not overturn the expectation that the Lord will come. He overturns the assumption that his coming will automatically favor Israel simply because she belongs to the covenant.
To explain this reversal, Amos paints a series of unforgettable pictures. A man escapes from a lion only to encounter a bear. Somehow he survives that attack, reaches the apparent safety of his own home, leans against the wall to catch his breath, and is bitten by a snake (Amos 5:19). Every place of refuge becomes another place of danger because the true problem is not outside the house. It lies within Israel herself. The nation has spent years assuming that military success, economic prosperity, and religious activity prove God’s approval. Amos insists that they prove no such thing.
The prophet then explains why. Speaking through Amos, the Lord declares, “I hate, I despise your festivals… Even though you bring me burnt offerings and grain offerings, I will not accept them” (Amos 5:21–22). To modern readers, these words can sound almost contradictory. After all, had not God himself commanded these sacrifices through Moses? He had. The problem was never the sacrificial system. The problem was that Israel continued to perform the rituals of the covenant while neglecting the covenant itself.
This distinction is essential. At Sinai, the Lord did not redeem Israel merely so they could offer sacrifices. He redeemed them so they could become a holy nation reflecting his character before the world (Exod. 19:5–6). Their worship, their justice, and their daily lives all belonged to the covenant. When Israel oppressed the poor while faithfully observing the religious calendar, they divided what God had joined together. Their sacrifices continued, but their covenant faithfulness had disappeared.
Now Amos reaches the heart of the matter with one of the best-known verses in the prophetic literature: “Let justice roll down like waters, and righteousness like an ever-flowing stream” (Amos 5:24). Justice and righteousness are not alternatives to worship. They are the evidence that worship has become genuine. Israel’s festivals, songs, and sacrifices were meant to express covenant faithfulness. When that faithfulness disappeared, the rituals themselves became empty.
Amos therefore transforms Israel’s understanding of the Day of the Lord. At Sinai, the Lord came to establish his covenant with a redeemed people. In Amos, the Lord comes to examine that covenant. The Day of the Lord becomes the moment when the covenant King evaluates whether his people have remained faithful to the covenant he established. It exposes the difference between outward religion and genuine covenant faithfulness. Membership in Israel alone offers no protection if Israel herself has abandoned the God who redeemed her.
Amos establishes one of the defining principles of the prophetic tradition. Before the Day of the Lord brings salvation, it brings judgment. Before it vindicates God’s people, it reveals who truly belongs to him. Every prophet who follows Amos builds upon this foundation, enlarging the vision until the Day of the Lord encompasses not only Israel but every nation and, ultimately, the whole creation.
Isaiah: The Day the Whole World Belongs to the Lord
If Amos corrects Israel’s understanding of the Day of the Lord, Isaiah enlarges it. Amos teaches that God’s coming begins with covenant accountability. Isaiah asks a different question: What happens when the God of Israel comes to reign over the whole world? His answer transforms the Day of the Lord from a warning directed primarily at Israel into the great hope toward which all history is moving.
Isaiah began his ministry in Jerusalem during the second half of the eighth century B.C.E., when the Assyrian Empire was rapidly becoming the dominant power of the ancient Near East. City after city fell before its armies. Smaller nations survived only by making political alliances or paying tribute to stronger kingdoms. In this world, military strength appeared to determine the future. Every empire credited its victories to its own gods, and every king sought security through armies, wealth, and diplomacy. Isaiah looked beyond these shifting political realities and announced a startling truth: history ultimately belonged neither to Assyria nor to Judah. It belonged to the Lord. The Day of the Lord would reveal that every human kingdom stood beneath the authority of Israel’s God.
Isaiah introduces this vision in chapter 2. “The Lord Almighty has a day in store for all the proud and lofty” (Isa. 2:12). As the chapter unfolds, Isaiah names everything people trust instead of God. He speaks of the cedars of Lebanon, famous throughout the ancient world for their height and strength. He mentions fortified walls, merchant ships, accumulated wealth, military power, and idols crafted by human hands. At first glance, these images seem unrelated, yet together they describe every place human beings seek security apart from their Creator. Some trust political power. Others trust economic prosperity. Still others trust military strength or religious idols. Isaiah gathers them all into one picture because the Day of the Lord exposes every false foundation on which humanity attempts to build its future.
The climax of the chapter explains why. “The arrogance of man will be brought low and human pride humbled; the Lord alone will be exalted in that day” (Isa. 2:17). Isaiah is no longer speaking only about Israel’s covenant faithfulness. He is speaking about the entire human race. The Day of the Lord reveals who truly governs history. Every rival authority eventually gives way before the kingship of the Lord.
Isaiah develops this theme further in chapter 13, where the language becomes strikingly cosmic. “The stars of heaven and their constellations will not show their light. The rising sun will be darkened and the moon will not give its light” (Isa. 13:10). Modern readers often wonder whether Isaiah is describing literal astronomical events. Before asking that question, however, it helps to understand how the prophets used this kind of language. Throughout the ancient Near East, the sun, moon, and stars represented stability, permanence, and authority. Nations associated heavenly bodies with the gods they worshiped, while kings often claimed that their rule reflected the order of the heavens. Isaiah announces that when the Lord comes, every competing claim to authority will fade before the Creator himself. The created order responds because the One who established it has entered history as its rightful King.
Yet judgment is only half of Isaiah’s vision. The Lord comes to remove evil because he intends to restore his creation. In chapter 11, Isaiah introduces a figure who stands at the center of that restoration: “A shoot will come up from the stump of Jesse” (Isa. 11:1). Jesse was the father of King David. By Isaiah’s day, David’s royal house appeared to have been cut down like a tree felled in the forest. Isaiah’s image is therefore deliberate. Although the Davidic kingdom appears dead, God will cause new life to emerge from what seems like a lifeless stump. The promised king will rule with perfect justice because “the Spirit of the Lord will rest on him” (11:2). Under his reign, the scattered people of Israel will be gathered, justice will replace oppression, and peace will characterize the created order itself. Isaiah’s famous picture of the wolf dwelling with the lamb expresses more than harmony among animals. It portrays a creation finally restored to the peace God intended from the beginning.
This restoration unfolds through another image that becomes increasingly important throughout the prophets: a Second Exodus. Israel’s first exodus brought God’s people out of slavery in Egypt and into covenant at Sinai. Isaiah now promises an even greater act of redemption. God will gather his dispersed people from the nations just as he once gathered them from Egypt. Rivers will once again divide before them. A highway will appear through the wilderness. The language deliberately echoes the book of Exodus because Isaiah wants his readers to understand that Israel’s first redemption pointed beyond itself. God was preparing his people to expect another act of deliverance that would surpass the first.
By the close of the prophetic era, the Day of the Lord had become one of Israel’s defining hopes. The prophets had expanded the pattern first revealed at Sinai into a sweeping vision of God’s future intervention in history. He would judge evil, vindicate his people, establish his kingdom, and renew creation. Yet when the prophetic voice fell silent, those promises remained unfulfilled. The story therefore did not end with Malachi. It entered a long period of waiting that shaped the world into which Jesus was born.
Part II will be posted soon!
Jill Szoo Wilson 